In 2010, then-Defense Secretary Robert Gates made waves when he ordered the Pentagon to take a hard look at the Marines to determine what, if any role they would play in the future of warfare.

“All of the military services have been challenged to find the right balance between preserving what is unique and valuable in their traditions, while at the same time making the changes necessary to win the wars we are in and prepare for the likely future threats in the years and decades to come,” he said. “Looking ahead, I do think it is proper to ask whether large-scale amphibious landings along the lines of Inchon [the Marine’s invasion of the Korea peninsula in 1950] are feasible.”

The review, which was completed in 2011, recommended the Marines shrink the size of their force dramatically and make other cuts that would lessen their strength. But the review did little to quiet speculation among the defense and policy community in Washington. There are lingering questions about the future of the Marines, with some suggesting that their missions are better conducted by the Army, Navy and Special Forces.

“They’re a service in search of mission,” said Gordon Adams, an American University professor and defense budget expert.

Because of this lack of mission and ongoing budget pressures, the Marines are becoming an endangered branch. In the age of DOD austerity, they represent low-hanging fruit that could easily be picked from the Pentagon’s tree.

FATE IN THE HANDS OF THE NAVYThe Marines, while considered a separate branch of the military, are actually part of the Navy. They’re often referred to as the “infantry of the Navy.”

“The Marines don’t have a separate fiscal existence. They are a wholly owned subsidiary of the Navy,” Adams said.

The Marines are funded through two different mechanisms. For 2014, President Obama has proposed a Marine operations and maintenance budget of $6.2 billion, slight increase from the $5.9 billion it received last year. This money is given directly to the Marines.

But the Navy has authority over the Marine’s personnel budget–expected to be $12.9 billion in 2014. This means that Navy brass can decide how it pays to train, house, feed and maintain readiness of the troops.

Because of this, according to Adams, the Marines often find themselves the victims of Navy spending fights. At a time when DOD is facings years of spending cuts, funding for the Marines is emerging as a bargaining chip in budgetary poker played among Navy commanders.

“They’ve always had a struggle on the budgetary side in the Navy,” Adams said. “If acquisition is going south, it’s going to put the squeeze on the Marines.”

SMALL BUDGET BUT NO MISSION The Marines’ small budget and relatively small force size might seem like an advantage. They are in the process of scaling down their forces from a peak of 202,100 to 182,100 by 2017 – a drawdown that was quietly announced last year. Their $19.1 billion budget is also considered tiny compared to other Pentagon programs.

In this case, small size and budget are working to the Marines disadvantage. They’re not “too big to fail,” and their moribund mission is reflected in a force that hasn’t performed amphibious assaults for 73 years.

This problem became acute during the Afghan war. The Army was conducting the majority of the ground offensives, and Special Forces were performing many of the high-risk missions once performed by Marines. The other military branches were marginalizing them while illustrating just how outdated their core competency had become.

Gates said as much when he referenced Inchon. In another speech in 2010, he said, “the Marines do not want to be, nor does America need, another land army. Nor do they want to be, nor does America need, a “U.S. Navy police force.”

The future of warfare is unlikely to require amphibious assault capabilities. According to nearly every future threat assessment, the United States needs to focus on counterterrorism operations and cyber warfare, not for an invasion of China.

Capitol Hill has taken notice. In 2011, it cancelled the $15 billion Expeditionary Fighting Vehicle program. It wasn’t just cost overruns that doomed the program – both the Pentagon and lawmakers have long shown the ability to tolerate wasteful programs. Lawmakers and Pentagon planners determined that the vehicle was no longer needed.

FRIENDS IN HIGH PLACESThe Marines are likely to survive not because their core competencies are vital to national security, but because they have allies on Capitol Hill who do not want to be responsible for killing a beloved service branch, says American’s Adams.

“I think the Marines will survive because we can’t let go of anything,” he said. “They have a lot of friends on the Hill who want to say, ‘Semper Fi! We’re going to save the Marines.”

But Adams added, “It’s a dead mission. It’s an old mission,” referring to amphibious assault. “But it’s at the heart of the Marines’ sense of self.”